Technical Field
The present application relates to the production and extraction of radioisotopes from a source compound.
Description of the Related Art
Diagnostic radiopharmaceuticals may include radiolabeled molecules used to provide information about various parts and/or functions of a patient's body (e.g., tumour cells, neuroreceptors, cardiac blood flow). A number of different radioisotopes have been used for these purposes, such as single photon emitters (e.g., 99mTc, 201Tl) and positron emitters (e.g., 11C, 18F).
99mTc is a well-known radioisotope used for various diagnostic procedures. Because the half-life of 99mTc is only 6.02 h, this radioisotope is typically delivered to the medical practitioner in the form of the parent radioisotope, 99Mo, which has a longer half-life of about 65.9 h. The 99mTc is then obtained from the decay of the parent 99Mo.
99Mo may be produced via an 98Mo(n,γ)99Mo reaction using neutrons from a nuclear reactor or from a neutron generator. Alternatively, 99Mo may be produced via a 235U(n,fission) reaction. However, both reactions have their disadvantages. For a 98Mo(n,γ)99Mo reaction, the yield of the 99Mo is diluted by the presence of the isotopic contaminant, 98Mo. As a result, the product has a relatively low specific activity (activity/mass) and final total activity. Such a 99Mo product is not particularly useful in the commercial context. For a 235U(n,fission) reaction, a relatively large amount of waste products are generated along with the 99Mo. Furthermore, the use of highly enriched uranium, which is the conventionally preferred target material, raises national security issues. On the other hand, the use of low enriched uranium has the problem that much more of the uranium is needed for the target, and more waste product is produced.